A map can become a more interesting source when approached through its own presentation. Before comparing it with a familiar view of a place, note its title, date information, scale and legend where these are available.
Describe the features that receive emphasis and those that are absent. Keep your observations tied to the particular map rather than assuming that every blank area represents an empty landscape. An unanswered question may concern the map itself as much as the place.
Choose one small area for closer comparison with another identified source. Record the dates and purposes of both items. Similar outlines do not remove the need to examine how the information was selected and presented.
Finish by writing what the comparison adds to your original question. A map study need not reconstruct an entire town. One carefully explained feature can provide a useful piece of local research while leaving the larger landscape open to further enquiry.